When using the excellent formidable library to handle file uploads, I needed to get a count of the number of files unloaded in a multi-part form. Javascript arrays have a .length property that you can use, but objects do not. I instinctively typed:
1 | files.length |
Which returned undefined. So if there is no length property present, an easy way to count the number of keys or properties of an object in ES5-compliant javascript environments like Node.js is to use the Object prototype directly:
1 | Object.keys(files).length |
A little more typing, but it is fast, efficient, and most importantly: already built-in.
